Portable insulation blankets are used in the construction industry to protect freshly poured concrete from freezing. An example of a concrete insulation blanket is shown by Brock in U.S. Pat. No. 3,420,022. This concrete insulation blanket has a seamless water impervious cover surrounding one or more sheets of flexible synthetic plastic insulation material. The cover is a polyolefin film. The cover surrounds a core of insulating material comprising expanded closed cell polyethylene. Other blankets have been used having cores of glass fibers. Examples of these types of blankets are shown by Corwin et al. in U.S. Pat. No. 2,927,626 and Katz in U.S. Pat. No. 3,162,566. The construction industry has established safety requirements and standards for construction materials. These requirements include surface burning characteristics of the construction materials. A current standard is the ASTM designation E84-68. Other organizations, as Underwriters Laboratories and Factory Mutual, have developed standards for flame resistancy for construction materials. The film covers in the blankets currently in use, as described above, are not fire or flame resistant.